1. Technical Field
This invention relates to a heating device of assembled cast panel construction of cast iron or other suitable material.
2. Background Art
Relevant prior art is represented by the following enumerated U.S. Pat. Nos., to wit: 556,098 (Johnson et al.); 564,804 (Steinhoff); and 4,232,051 (Auerbach et al.).
Steinhoff has a cylindrical firebox comprised of a lower section which is divergent and an upper section which is convergent and terminates in a dome. Steinhoff lacks Applicant's structure of upper and lower side cast panels which present and define flat surfaces inwardly facing Applicant's combustion chamber. Steinhoff lacks fire brick, whereas Applicant has fire brick emplaced in diverging relationship with his lower side cast panels to reflect heat upward. Applicant has a flat top wall, whereas Steinhoff has a dome. Applicant stops the heat at his flat top wall to further concentrate and maintain the heat in the upper combustion chamber half. Steinhoff does not predicate any functional attribute whatsoever to the shape of his fire box. Applicant's heating device is 40% to 50% more effective in forcing the heat to concentrate and maintain itself in the upper half of his combustion chamber above the creosote deposition temperature so that creosote will not form from the flue gases.
Certified on-going inspections by impartial experts with respect to Applicant's heating device--embodied as having side walls which diverge upwardly and outwardly, then converge upwardly and inwardly, and joined by a top wall that has a horizontal flat surface that inwardly faces the combustion chamber, with the surfaces of the side walls which inwardly face the combustion chamber being flat as well, and with a water boiler tube arrangement located in the upper half of the combustion chamber--confirm that the structure of Applicant's heating device is unique in that such flat top wall further concentrates and maintains the heat in the upper combustion chamber half; that this structural feature is 40% to 50% more effective (as compared, for example, to a dome-like structure) in forcing the heat to concentrate and maintain itself in the upper half of Applicant's combustion chamber with the functional result that Applicant's heating device maintains itself above the creosote deposition temperature; and such on-going inspections have confirmed that there is no evidence of creosote in the interior of Applicant's heating device nor in the chimney operatively connected with Applicant's heating device.
In Johnson et al., the title is misleading as to the same being a furnace for the reason that their structure is not a furnace per se, but rather an attachment or insert for the inner sidewalls of a sheet metal furnace-casing (see page 1, column 1, lines 13-18). Johnson et al. has concave-convex inner metallic lining-plates which define air-circulating chambers to prevent burnout and burnthrough of the sheet metal furnace-casing wall. No heat is reflected upward in Johnson et al., nor is any heat concentrated because of the semi-circular configuration. Johnson et al. further differs structurally from Applicant's heating device in that Applicant's lower side cast panels diverge upwardly, whereas in Johnson et al. the lower side cast panels converge upwardly. In Johnson et al., the inventors were confronted with the problem of burnout of the metallic sides of their furnace-casing laterally at the edges of their grates (page 1, lines 13-18, lines 58-67, lines 74-93) at which locus the intense fire would cause the most damage. Their lining-plates have air-circulating notches to ventilate the chambers formed by the lining-plates and their furnace-casing and allow a continuous circulation of air therethrough from the ashpit. Because Johnson et al. keep their furnace-casing cool to prevent lateral burnout and burnthrough, creosote will be formed in the region of their air-circulating notches. Contrastingly, the structure, arrangement and use of Applicant's diverging fire brick lying against his lower side cast panels are not to lower the temperature but to reflect such heat upward where same is forced to be concentrated and maintained by Applicant's converging upper side cast panels and with such heat being further concentrated and maintained by Applicant's flat top wall. As compared to the semi-circular interior wall surface in Johnson et al., Applicant defines his top wall as having top cast panels joined together to present a horizontal flat surface inwardly facing his combustion chamber. Applicant's top flat inward surface defines and subtends an obtuse angle with each of the flat inward surfaces of the upper side cast panels. The flat inward surface of each upper side cast panel defines and subtends an obtuse angle with each flat inward surface of each of the lower side cast panels.
Auerbach et al. have a coal-burning furnace or boiler comprising simply welded steel plates defining a combustion chamber protected by fire brick with a horizontally disposed water tube configuration which functions as a baffle to provide and effect 180.degree. change in direction of the heat and products of combustion in one direction along the bottom of the water tubes and then to reverse the heat flow direction along and upon the top of the water tubes. In Auerbach et al. the walls are square and vertical, no heat is directed upwardly from their fire brick because the walls and fire brick are all vertically disposed. In Auerbach et al. the reason their fire brick are vertically disposed against their upper and lower firebox halves is not to reflect heat upward as claimed by Applicant, but rather to prevent burnout of their firebox halves.
As a matter of fact, sheet metal devices available buckle and render because of temperature changes. Because of their welded construction, there is no give to the sheet metal upon expansion and contraction. Consequently, such heating devices warp drastically and burn out within two to three years of use.
The object of the invention is to provide and dispose in the top area of the combustion chamber a coil of layers of connected steel water tubes operatively connected to a holding tank and expansion tank functioning as a boiler. The holding tank and expansion tank are located external of and above the heating device. The experimental model of such boiler demonstrates that creosote build-up in the heating device is significantly reduced, and in fact such on-going inspections certify the heating device to be creosote free, because the angled side walls function to reflect heat upward off the fire brick and to force such heat to concentrate in the smaller area at the top of the combustion chamber where the coil of water tubes is disposed and located, thereby heating water more quickly and efficiently. Moreover, the cooperating flat top wall structure further stops the heat to further and significantly aid in concentrating and maintaining the heat in the upper combustion chamber. Accordingly, the internal heat in such water-tube coil is maintained far above the critical 270.degree. F. temperature of creosote deposition from the flue gases. In addition, because of the cast construction of the heating device, heat is maintained at a more constant level longer, thereby further preventing creosote from forming. Furthermore, with the holding tank external of the heating device, any effect of such holding tank in lowering the internal operating temperature of the boiler below the critical 270.degree. F. creosote deposition temperature is eliminated. Another object of this invention is to contribute to the solution of the problem encountered with sheet metal heating devices by providing a heating device of assembled cast panel construction. These castings of iron or other suitable material will expand separately, independent of each other and of one another, and as much as a thirty-second of an inch to a square foot of surface panel depending upon where a particular panel casting is located in the assembled heating device. Naturally, the unprotected cast panels in the top area of the combustion chamber get much hotter than the cast panels in the lower area of the combustion chamber protected by fire brick, and comparatively hotter than the panels defining the ashpit. Such cast panels can expand and contract with the extreme temperature changes in the combustion chamber. By practicing this invention and using separate, smaller cast panels, the problem is eliminated and the heating device will have a much longer stove life, perhaps as long as 30 to 40 years.